Internal gauge



June 23 1953 E. w. GRAHAM :TAL 2,642,67-1

INTERNAL GAUGE Filed May 3, 1950 i, 2 Sheets-Sheet 1 INVlVTOR. 52W/N W GRAHAM WALTER O. MIA/75L E. W. GRAHAM ETAL June 23, 1953 INTERNAL GAUGE 2 Sheets-Sheet 2 Filed May 5, 1950 L Amm. www MGM. mm@ Y R .NE /7 MM. m. w if w l 8 lPatented June 23, 1953 INTERNAL GAUGE Erwin W. Graham, Parma Heights, and Walter O.

Mintel,

Shaker Heights, Ohio, assignors ,to` vCleveland Instrument Company,

Cleveland,

Ohio, a corporation of Ohio Application May 3, 1950, Serial No. 159,7 34

13 Claims. 1

This invention relates to interna'l micrometers or gauges and more particularly to internal micrometers or gauges of high sensitivity-which are capable of making measurements to within a few millionths of an inch. l

Heretofore the gauging of internal diameters has' been (difficult and hasrequired aiconsiderable amount of skill on the part of the person making the measurements. The reason for this is that the measurement must be made along a diameter ofthe opening being measuredand perpendicular to the axis of the opening; deviation from a true diameter gives a reading that is too small, deviation from the perpendicular gives a reading that is too large. The dificulty is aggravated because of the'fact that in order to obtain highly accurate measurements, at least one of the measuring elements-should make point contact with thesurface of the work to be measured and'y theother must make no more than line contact; if both ofthe measuring elements make line or surface contact with the work being measured, then surface irregularities and the presence of dust, dirt or surface 'lms may seriously impairy the accuracy of the measurements1- Therefore, Vinternal gauges Which have been dependent upon -line or 'surface contacts of both measuring elements in order to position the gauge within the opening being measured have not been suitable for measurements involving very high precision.v`

A general object of the present invention, therefore,` is the provision of an internal micrometer, gauge or comparator capable-'of making measurements to an accuracy of Within ay few millionths of an inch. Another object of the pro- Avision of an internal micrometer or gauge'bythe use ofi which accurate measurements of internal diameters can be made *without requiring any particular.'r skill or experience on the part of the operator.v VA further object is lthe provision'of a gauge which issubstantially self-aligningso that the gauging element automatic-allytakes acorrect position within the opening to be measured. Other objects are the provisionof an internal gauge which is capable of measuring diameters near the endsfof openings; the provision of` a gauge that can be adjusted easily and rapidly to a standard dimension by meansof gauge blocks or the like; the provision of a gauge in whichvthe zero position 'can be 'adjusted readily; theprovision of a gauge in which the effects vof temperature changes are minimized; the provisionlof-a gauge-embodying interchangeable gaugehea'ds so that the gauge can be .adapted for a Wide range of .measurements simply by changing thefgage e V 2 y heads while utilizing the same gauge bodyv and indicating instrument.. '1 y lFurther objectsand advantagesof the invention will `become apparent from the following de-A scription offapreferred form thereof, reference being made to the accompanying drawingsiin which Figure'l is aperspective View illustrating the complete gauge including a gauge head and body embodying'the present invention and' an electronic indicator associated with the gauge; Figure 2 is a longitudinal section through the center of the gauge shown in Figure 1 showing the gauge head in position With a sleeve to be measured; Figures 3,4, 5 and 6 are transverse sections through the gauge of Figure Ztaken alongthe lines v3 3, 4 4, 5 5 `and 6-6, respec-y tively.- of Figure 2; Figure 7 is an end view ofthe handleportion viewed in the direction of the ar- .rows L of Figure 2; Figure 8 is a transverse` section through the gaugeof Figure 2 taken along the line 8-8 of Figure 2; Figure 9 is a perspectivev` view similar to Figure 1 but showing a head "of larger diameterjattached to the gauge body'of l Figures 1Y and 2;` Figure l0 is a partial longitudinal section throughv the gauge of Figure 9; 'and Figure 11 is a transverse .section taken along the line II-ll of Figure Y10. p Preferably, a gauge made according to apreferred form of our invention comprises a gauge vhead embodying an anvilA or fixed contact member adapted to make a line contact with the internal surface ofV an opening to be measured and a movablecontact 5 member or gauging Vpoint y I adapted to make pointfcontact Withgthe surface ,the iiXed anvil in proper. contact with the surface even though thesurface may be tapered slightly as is usually theca'se.' Therefore, the distance between the fixed anvil and the movable lgauging point is measured-along aline which is'almost` precisely'at rightangles to the line of*` contact of v the anvil with vthe surface, and this line maybe considered to be a diameter of a circle or cylinder Y 3 defined by the xed anvil and the contacting elements of the particular locating piece immediately adjacent the gauging point or a diameter of the right circular cylinder defined by the anvil and the contacting elements of the locating pieces. The locating pieces locate the gauge head in the openingto be measured so that the center of the circle or the axis of the cylinder, whichever it is considered to be, almost precisely corresponds with the center or axis of the opening;

Hence, the measuring point is located, with only f a very small error, on a diameter of the opening to be measired, which diameter passes through the line of contact of the xed anvil with the surface of the opening. v l

The gauge head is removably secured to a handle member which preferably includes a pickup embodying an armature movable by the gauging point; the output of the pickup is amplied by suitable electronic circuits and indicated on a meter calibrated to read in terms of deflection on either side of a central zero. The pickup .and the support for `the gauging point are adjustably mounted in the handle so that the gauge readily can be set to zero position. Preferably the pickup and indicating circuits are constructed in accordance with the disclosure of the copending applications of Michael Bozoian Serial No. 771,528, nled August 30, 1947, now Patent No. 2,508,370, and Erwin W. Graham Serial No. 785,315, filed November 12, 1947, both of which are assigned to the assignee of this application.

Referring now to the drawings, Figure 1 shows a gauge made according to a preferred form of the invention and. comprising a body or handle Y portion I0 and a gauge head indicated in general at II. A conductor or cable I2 connects the gauge proper with theV electronic circuits contained within the cabinet I3, the zero center vmeter I4 -being mounted on the front face of the cabinet. A switch I5 is provided for turning the electronic circuits on and off. The selector switch I6 is employed to make available two different degrees of sensitivity ofthe instrument I by changing the amount of amplification by Wellapplication, and will not be described in detailA herein. For purposes of the present invention, which relates primarily to the construction of the gauge itself, it is Asufticientvto state that the electronic apparatus amplifies the signal" currents generated in the gauge head andapplies them to the meter 'I4 so that the needle of the meter kgives an accurate indication of the direction and magnitude of deviations of the position of the gauging point from a preset zero position.

As shown particularly in Figures 1 to 5 the gauge head II comprises a generally cylindrical body'portion 2Q in which the anvil or fixed contact member 2l is rigidly supported. Anvil 2| is preferably composed of tungsten carbide or other very hard material; the anvil is ground to a radius substantially smaller than the radius of the opening to be measured and vthus'makes Vline contact with the interior of the opening to be measured such as, for example the interior of the sleeve S, the contact line of member 2| being parallel to the axis of the body 20. Body 2li may be composed of steel. VThe forward end 4 of the body is recessed as at 22 (see Figures 3 and 4) to receive the spring pressed locating pieces 23, 24 and 25. These locating pieces are substantially identical and are generally Y- shaped in section. The lower legs of the Ys, indicated at 26, 21 and 28, respectively, make sliding nts inthe slot or-rec`ess22 Vof the body 20, the movement of the locating pieces in the slot being along the diameter of the measuring head that passes through the line of Contact of the anvil 2| with the sleeve S; this diameter is indicated by the center line-in Figure 3.

The locating pieces 23, 24 and 25 are preferably constructed of the same material as the body 2U and are provided with Work contacting surfaces or projections 29 and 30, 3l and 32, and 33 and 34, respectively; they are ground to small radii to provide convex cylindrical surfaces extending parallel to the axis of the body, and thus make line contact with the interior surface of the sleeve, the lines of contact being parallel to the axis of the body 2IJ. A The projections are rounded at their ends as shown in'Figure 2.so that'the head rmay be easily inserted within an opening to be measured. Y.

The locating pieces 23, 24 and .'25 are heldjin position against endwise displacementqby means of an end plate 36 which is Ysecured tothe lbody 2l! by screws 31. The locating pieces are urged radially outwardly to engage the internal; sur-,- face to be measured by'means of springsthe ends of which are seated in openings 39 and 4I) in the bottoms of the locating pieces and-,the bottom of the slot 22, respectively. Outward movement of the locating pieces is limitedfby the pin 4I which is secured in ,the end plate V3 6,

, extends through slots 42 inthe locating pieces and into the body 20. the spring pressed locating pieces hold the anvil 2| in line contact with the internal surface of the' openings to be V,measured so that the-axis of the gauge head is substantially parallel with n the axis of the opening, and locate the/center ofopening when the gauge head is properly posi-y tioned in the opening to be measured. The-Work contacting end of theV .gaugenpoint 45, Ywhich may becomposedof sapphire or othervery-hard material, is preferably Vspherical in shape, and of small radius so that it will makepoint contact vwith the interior surface of the opening.

vIn order to support the gauging point gandto translate the position of the gaugingpoint to indications of a meter or the like, thegauging .point is mounted near the end'of leg 46 of a bell crank lever 41. The bell crank 41 is pivotally mounted on the movable frame member 48 of the handle vportion I0 of the. gauge by meansof the hinge spring 49. The leg '46 of the bell crank extends outwardly from-the ih-andle member .I0 through the slot injthe Ibody 20 ofthe gauge head :and aligned slots 5I and` 52 of thelocating pieces 25 and 24 respectively, terminating in slot 53' offthe'locating piece 23, the gauging -point 45 projecting radially from substantially=themid portionv of the slotY 53; YThe other leg `F14-'of the bell crank is v'connected 'tcthe :pickup .indicated W ith A.this arrangement in general at 55; pickup 55 is carried by the movable frame mem-ber 48. Thus, the pickup is actuated by movement of the gauging point and bell crank with respect to the movable frame member 43, and these movements are used to operate the indicating meter or the like of the gauge as will be described below.

In order to support the gauge head II Iand locate it accurately with respect to the handle I so that the gauging point 45 will be located properly with respect to the locating 4pieces and anvil 2l, the gauge head is secured as by means of screw 55 to the end face 51 (see Figure 7) of the fixed fra-me member 58 of the handle I0. The end surface of the lbody 20 is vprovided with a projection 59 (see Figure 2) the edges of which are parallel to a diameter of the gauge head passing through the line of contact of anvil 2| and point of Contact of gauging lpoint 45 with the work. Projection 59 ts accurately into 'a groove 60 in the end face 5! in order to position the gauge head properly with respect to the handle. Screw 56 is readily accessible through the passageway 6I provided by aligned openings in the end plate 35 and locating pieces 23, 24 and 25 so that the gauge head can be removed as a unit simply by removing screw 5S from the fixed frame member 58.

The ymovable frame member 43 of the handle is accurately located ywith respect to the xed frame member 58 by means of the pin 63 on which one end of the frame member 48 is pivotally mounted; the ends of pin 63 are accurately fitted into openings in the iixed frame member 58, The other end of the movable vframe member 48 is'provided with a projecting portion 54, the opposite sides of which are engaged by set screws 65 and 6E in fixed frame member 58 and which may be adjusted by means of a tool inserted through openings 61 and 58, respectively, to secure the movable frame member 43 in a desired position of adjustment with respect to the xed frame member 58. The adjusting movement of the movable frame member is about the pivot pin 63 which is located in the fixed frame member at right angles to the groove B and hence also at right angles to the .projection S of the head and to the diameter to lbe measured. Inasmuch as the gauge head, and therefore the anvil, are rigidly mounted on the fixed frame member 5B, while the gauging point and pickup are carried by the movable frame member 43, adjustment of the movable frame member about the pivot 63 adjusts the position of the gauging point with respect to the anvil without laffecting the relationship between the gauging point and the pickup. Hence the adjustment of the Inovable frame member can be utilized to set the gauge to a zero position.

While any convenient type of pickup or indicating mechanism can be employed to indicate the direction and extent of the deviations of the gauging point 45 from a predetermined zero `position, we prefer that the pickup mechanism 155 be constructed generally in accordance with the disclosure of the aforesaid applications of Erwin W. Graham and Michael Bozoian. Such a pickup may comprise a substantially E-shaped eld structure 10 which is rigidly mounted in the channel-section central portion of movable frame member 48 (see Figures 2 and 8) and disposed in a recess 1I in the iixed frame member 58. The eld structure 1t provides three ypole pieces 12, 13 and 14 on which coils 15, 16 and 11 are wound, The eld structure is preferably laminated and composed of transformer iron and the projecting ends of the pole pieces '12, 13 and 14 are preferably of rectangular cross section as shown.

Movement of the bell crank 41 caused `by Idisplacement of the gauging point d5 is transmitted through a spring connecting link 'IS to the ferromagnetic armature 19 carried on a non-magnetic stem 19a which is supported for substantially longitudinal movement close to the ends of .the pole pieces 12, 'I3 and 14 by spring links 80 and BI. The links preferably are constructed in the manner disclosed in the aforesaid Graham application and are secured rigidly to the .base portion of the eld structure 10 as by cap screws 82 and 83. With this arrangement, movement of the gauging point results in corresponding longitudinal movement of the armature with respect to the vpole pieces 12, 13and 14; the movement of the -armatu're changes the flux paths between the end -coils 15 and 11 which constitute pickup coils and the central or exciter coil 16. Inward movement of Ithe gauging point moves the armature to the right as shown in Figure 2 of the drawings, increasing the flux linkage between the exciterV coil 1t and the pickup coil 1'! and reducing the linkage between the exciter coil 15 and the pickup coil '15. Outward movement of the gauging point moves the armature 19 to the left and has the `opposite effect on the flux linkages of the coils. The armature is urged to the left and the gauging' point is urged outwardly with the desired gauging pressure by the coil spring 34 which acts on the right-hand end of the armature.

As described in theaforesaid Bozoian application the exciter coil is preferably energized by low frequency alternating current, and alternating currents are therefore induced in the pickup coils 15 and 11. Whenv the armature 19 is in zero or mid-position, equal voltages are induced in the two substantially identical pickup coils; these are connected in series opposition to each other and therefore the output of the pickup is zero. Movement of the armature 19 in either direction from its mid-position results in an increase in the voltage induced in one of the pickup coils and a reduction in the voltage induced in the other. The magnitude of the output of the pickup depends upon the distance that the armature is displaced from zero position while the phase of the output is governed by the direction of the displacement. of the circuits described and claimed in the said Bozoian application, the output of the pickup is amplied and applied to the Zero center D. C.

meter I4 in such manner that the position of the needle of the meter gives an indication of the direction and amount of displacement of the armature from its zero position and correspondingly of displacement of the gauging point l45 from its Zero position; the circuits are such that the response of the meter to displacement of the armature is linear within the usable range. The circuits are stable and the sensitivity is such that displacements of the order of a few millionths of an inch are readily indicated on the meter.

In order to protect the pickup mechanism and to provide for convenient manipulation of the gauge, the xed frame 58, movable frame 48 and pickup 55 are all enclosed within a protective metal sleeve which fits closely around the xed member 58 and is secured thereto by screws 85. The sleeve is apertured to provide access By means l to the screws 65 and B6. The end of the fixed frame member 58 has a cylindrical recess which receives the cylindrical projection B1 of the insulating handle 88, the screws 86 extending through the flange 89 of the fixed frame member and into the projection 8l. The insulating handle 88 is preferably composed of wood or other material having relatively poor heat conductivity, provides a convenient grip for the operator and substantially prevents the heat of the operators hand from being transmitted to the gauging head sufliciently to affect the operation of the gauge.

The range of movement of the gauging point With respect to the anvil is necessarily small because of the high sensitivity of the instrument. In order to make the instrument adaptable to the measurement of articles of a wide range of sizes, We preferably provide gauging heads of different sizes for cooperation with a single handle or body portion Ill. A gauging head of a larger size than the head Il is indicated in general at I la in Figures 9, l and ll. The construction of this head is substantially identical with the head H previously described except for its greater size. Thus the head Ila comprises a body 20a, an anvil 2Ia, locating pieces 23a, 24a and 25a having contacting projections 29a and 30a, 3m and 32a, and 33a, and Ella respectively, and an end plate 36a. The locating pieces are urged radially by springs 33a to maintain proper contact of the projections and the anvil 2 la with the internal surface of the opening to be measured.

The head lla is secured to the body or handle I0 by screw 5&3, but in this instance because of the increased size of the head, the screw E is not disposed on the center of the head but is displaced therefrom so that when the head is assembled with the handle or body, the relation ship between the gauging point 45 and the locating piece 23a Will be substantially the same as the relationship between the point Q5 and the locating piece 23 of the gauge shown in Figures 1-8 inclusive. Also, the work contacting projections 29a and 31m of the locating piece 23a and the work contacting projections of the locating pieces 2:3 and 25 are spaced farther from the gauging point e5, the arrangement being such that radii drawn from the projections 29a and 30a to the center of the head lla include an angle substantially equal to the angle included by the similar radii drawn from the projections Z9 and 353 to the center of the head Il. This relationship is preferably maintained in heads of varying sizes adapted for use with a single handle so that the centering action of the locating pieces will be substantially the same with all sizes of heads. The gauge head Ha is centeredV by the locating pieces with respect to the sleeve S in the manner previously described. The operation of the gauge is extremely simple. The power supply is turned on and the electronic devices in the circuit permitted to warm up for a few moments. Then the gauge is set to a zero position by, for example, inserting the gauge head into an opening of known dimensions and adjusting the position of the movable frame member 53 by means of the screws 65 and 65 until the needle of the meter lil is approximately at the zero position. Then the final adjustment of the needle to zero is made by the zero setting knob Il which varies an element in the circuit to adjust the position of the needle. Thereafter, it is only necessary to insert the gauge to a de- El sired position in an opening to be measured, whereupon the position of the needle of the meter I4 indicates the deviation of the opening beingY measured from the opening of known dimension which was used to set the gauge to zero.

The spring pressed locating pieces hold the anvil and the gauging point in proper position with respect to the Work without requiring any particular degree of care or skill on the part of the operator. Not only do the locating pieces and the anvil insure the positioning of the gauging point with great accuracy, but also errors due to the measurement being made along a line not precisely perpendicular to the axis of the open ing being measured would tend to give readings that are too large, while errors due to the measurement being made along a line which does not pass through the center of the opening would tend to give readings that are too small; thus the errors tend to cancel each other. The result is that repeated measurements checking within a very few millionths of an inch can be obtained by inexperienced operators. The meter reading is practically instantaneous; thus the taper of openings can be determined rapidly by moving the gauge head in and out of the opening, while out-of-roundness can be determined by rotating the gauge head in the opening. Bell mouth effects close to the ends of the openings can be measured because the gauging point is positioned near the end of the gauge. Inasmuch as the anvil makes line contact with the Work while the gauge point makes point contact, the presence of surface films and the like on the Work does not seriously affect the accuracy of the measurements. The anvil is pressed against the Work with uniform pressurev by the springs which urge the locating pieces outwardly and the gauging point is urged into engagement with the work with uniform pressure by the spring 84. Thus the pressure exerted on the work by the measuring elements is predetermined and constant and outside of the control of the operator, eliminating this variable from the results.

The device is compact and stury and can be utilized under shop conditions to obtain highly accurate measurements. Because of the arrange'- ment of interchangeable heads, a single gauging apparatus can be utilized with a number of heads for gauging articles of a Wide range of sizes.

Those skilled in the art will appreciate that various changes and modiiications can be made in the preferred form of the invention described herein. Therefore it is to be understood that the foregoing detailed description of the invention is given by way of example rather thanY limitation and that the scope of the invention is dened by the appended claims.

We claim:

1. .An internal gauging device comprising a supporting member, a pickup disposed within said supporting member, an arm operatively connected to the pickup projecting axially of said supporting member beyond one end thereof and carrying a gauging point on the projecting portion thereof, said gauging point and arm being movable transversely of said supporting members a gauge head detachably secured to said supporting member, said gauge head and said supporting member having intertting parts accurately locating said gauge head on said sup- 9 with van'internal-surface to be measured and carrying on the opposite side thereof'a plurality of unitary Y-s'haped locatingy pieces, each of said locating pieces havingaf central recess opening on'the side of said gauge'head oposit'e said anvil anda work engaging projection'oneither side of said vcentral recess, the work engaging projections and recesses of the locating pieces being aligned witheach other, said arm'carryingrsaid gauging point being disposed in the opening provided by said aligned recesses and being spaced from the walls of said recesses, said locating pieces being independently movable andresiliently urged outwardly away from said anvil in a direction parallel to a line passing through the highest element of said cylindrical surface of said anvil and said gauging point, said gauging4 point being movable along said line.

2. An internal gauging device according to claim l wherein the gauge head isncylindrical, and the work' engaging projections on thelocat-y ing 'pieces have cylindrical surfaces adapted to make line contact' with the surfaceto be measured along lines parallel to the' line of *contact of the vanvil therewith. v n

l3. An internal gauging device according to claiml, vwherein the interlitting parts on the gauge head andsupporting member comprise a projection on one of `said members and agroove on the other, said groove and projection extending parallel to said line passing through kthe highest velement of said cylindrical surface of said anvil and said gauging point.

' 4. An internal lgauging devicev according to claim l'wherein thes'upport for the arm and the pickup comprises a single'movable Vframehrnember'disposed within the supporting member, the position of the movable frame member'with ref spect to the remainder of the supporting member being adjustable; whereby the position of the arm and gaugingpoint with respect to the anvil can beuadjusted without changing the relationship between the gauging point and thepickup.

5.`An internal gauging device comprising a supporting member, Aa pickup-disposed within the supporting member, an arm' operatively 'connected to thepickup 4projecting axially of said supporting member beyond one end thereof land carrying a gauging point on the projecting por"- tionthereof-.said gauging point and armn being movable transversely of said' supporting mem# ber, a gauge head mounted on said supporting member, said gauge` head carrying one'one side thereof "a fixed anvil4 member having a convex surface adapted to engage an internal surface to be measured and carrying on Ythe opposite side thereoffa -Y-shaped locating piece having a central recess opening on the side'o'f said gauge head opposite said anvil and work engaging p'rojec` tions on either side of said central recessfsaid gauging point being disposed in said recess and said arm being spaced from the walls of said recess, said locating piece being resiliently urged outwardly away from said anvil in a direction parallel to a line passing through the highest point of said convex surface of said anvil and said gauging point, said gauging point being vmovable along said line.

6. An internal gauging device comprising a supporting member, a pickup disposed within said supporting member, an arm operatively connected to the pickup projecting axially of said supporting member beyond one end thereof. and carrying a gauging point on the projecting portion thereof, said gauging point and arm being movable transversely of said supporting member, a gauge head secured to said supporting member, said gauge head carrying one one side thereof a xed anvil member having a convex surface adapted to engage an internal surface to. be measuredr and carrying on the opposite side thereof av pluralitykof locating pieces, said locating pieces being resiliently urged outwardly away from said anvil, each of said locating pieces having two circumferentially spaced work engaging projections, said work engaging projections and said anvil definingk circles the centers of which substantially coincide with the center of an opening to be measuredwhenv said gauge head is inserted in such an opening, at least one of said locating pieces having a recess therein disposed between the work engaging projections thereof, said arm projecting into and said gauging point being disposed in said recess` and spaced from the walls thereof, the line of movement of said gauging point coinciding with a diameter of` such a circle, which diameter passes through a point of contact of said'- anvil with the surface of such opening. -V

7. yAn internal gauging device comprising an elongated supporting member, a pickup disposed within said supporting member, the pickup embodying an armaturevmovable longitudinally. of saidsupporting member, a bell crank'pivotally mounted in the supporting member,'one arml of said bell crank extendingv transversely ofi said supporting member and being connected to said armature by a flexible link, the other arm projecting axially of the supporting member lbeyond one end thereof and 'carrying a gaugingk point on the projectingv portion thereof, la-gaugehead se-r tion awayfromsaid anviland along a line passing through the highest point of said convex surface ofv saidanvilV and the center of'said gauge head, each ofsaid locating pieces having a central recess openingI on the rside'of said gauge head opposite said anvil'and work engaging pro--v jections-on yeither side of "said: central recess, said work engaging proj ections'- andl .recesses xofr said locatingfpieces being aligned and extendingparalr.

letto-the axis of saidfgauge head, the arm of saidbell crank'carrying said gauging point being disposed in the opening provided by said aligned recesses and being spaced from the Walls thereof and said gauge head being oriented with respect to. said supporting member by said interfitti-ng parts sin such manner that said gauging point lies on and is movable along said line passing through a point of contact of said anvil with a surface to be measured and the center of said gauge head.

8. An internal gauging device comprising an elongated supporting member, a pickup disposed within said supporting member, the pickup embodying an armature movable longitudinally of said supporting member1 a bell crank pivotally mounted in said supporting member, one arm of said bell crank extending transversely of said supporting member and. being operatively connected to said armature, the other arm extending axially of said supporting member and carrying a gauging point, a gauge head secured to said frame adjustably mounted on the main frame Y for pivotal movement with respect thereto, a pickup disposed within said supporting member and mounted on said sub-frame, an arm supported by said sub-frame, said arm being operatively connected to the pickup and projecting axially of said supporting member beyond one end thereof and carrying a gauging point on the projecting portion thereof, said gauging point and arm beingmovable transversely of said supporting member, a gauge head secured to the main' frame of said supporting member, said gauge head carrying a fixed anvil member adapted for cooperative use with said gauging point in making measurements, and means for adjusting the position of said sub-frame with respect to said main frame whereby the position of said gauging point with respect to said anvil may be adjusted without varying the relationship between said gauging point and said pickup. A

10. A gauging device comprising a supporting member comprising a main frame and a subframe adjustably mounted therein, an anvil xed with respect to said supporting'i'nember, a pickup disposed within said supporting member and mounted on said sub-frame, an armrsupported by said sub-frame, said'arm being operatively connected to the pickup and projecting axially of said supporting member beyond one end thereof and carrying a gauging point on the projecting portion thereof, said gauging point and arm being movable transversely of said supporting mein-Y ber, and means for adjusting the position of said sub-frame with respect to said main frame.'

, 11. A gauging device comprising an elongated supporting member, a pickup 'disposed within said supporting member, the pickup embodying an armature movable longitudinally of said sup-F porting member, a bell` crank pivotallymounted, in the supporting member, one arm of said bell crank extending transversely of said supporting' member and being connected to said armaturev by a flexible link, the other arm projecting axial'- ly of the supporting'member beyond one endV thereof and carrying a gauging point on the projecting portion thereof. i

12. A gauging device-comprising a supportingV member having a xed main frame and a sub-v frame pivotally mounted on the main frame,` a.'

' passes through a point ofv contact of said anvi- 12 pickup disposed within said memberand mounted on said sub-frame, a bell crank pivotally mounted on saidsub-frame, one arm of said bell crank beingoperatively connected to'said pickup, the other arm projecting from said supporting member carrying a gauging point on the projecting portion thereof, an anvil fixed with respect to said main frame, and means for adjusting the position of said sub-frame on itsvpivotal mounting on said main frame and thereby adjusting said gauging point with respect to said anvil.

13.y An internal gauging device comprisinga gauge head adapted to be inserted into an open--l ing to be measured and carrying on one side thereof a fixed `anvil member adapted to engage the surface of the opening and carrying on'v the opposite side thereofa plurality ofrslidably mount-v ed, aligned Y-shaped locating pieces,- saicllocating pieces being resiliently urgedv outwardly away from said anvil, each of saidlccating pieces hav ing a central recess opening on the side of said gauge head opposite said anvil and a work er1-f gaging projection on either vside of Said central recess, said work engaging projections and recesses of said locating pieces being aligned and parallel to the axis'of said gauge head, said work engaging projections and said anvil defining circles, the centers of which substantially coin-f cide with the center of an opening to be measured when said gauge head is inserted inf'such an opening, and a gauging point disposed in one of said recesses and anv arm extending through another of said recesses-and carrying said gaugingv point, said arm'A being spaced from the walls of said recesses, said gauging point being movable along a diameter of such a circle which diameter with the surface of such opening. l -V ERWIN W. GRAHAM. WALTER. o. MINTEL.

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